Parallel communication between circuit boards is limited by the number of input and output connections available on each circuit board and corresponding connector. To meet demands for increased numbers of reliable input/output connections, circuit board connectors were redesigned to have a high connection or lead density and to be adapted for mounting directly on the circuit boards.
As lead density continued to increase, problems arose with respect to mounting high density lead insertion connectors onto circuit boards. Bent leads and other related defects caused by manufacturing or handling procedures heretofore rendered manual alignment and mounting of these connectors impractical, both physically and economically. Alternative techniques such as reflow soldering and appropriately designed high density connectors were developed to avoid the problems related to manual lead insertion.